For example, Japanese Unexamined Patent Application Publication No. 8-196950 (Patent Literature 1), or WO01/02099 (Patent Literature 2) disclose a spray gun, in which a gun barrel of the spray gun is provided with a coating material nozzle that ejects a coating material flow from a coating material ejection opening of a tip end portion thereof, and an air cap that surrounds the tip end portion of the coating material nozzle and defines in a gap with the tip end portion a ring shaped slit that ejects an air flow.
The tip end portion of the coating material nozzle has a guide wall on a tip end surface thereof spreading from an inner periphery of the coating material ejection opening toward a tip end side, and a plurality of V shaped grooves on an outer periphery thereof channeled from a predetermined position on a rear end side to the guide wall in a longitudinal direction. The guide wall is adapted to restrict the coating material flow ejected from the coating material ejection opening. The V shaped grooves are adapted to guide a part of the air flow toward a front side of the coating material ejection opening.
In the spray gun thus configured, when coating material is ejected from the coating material ejection opening to form the coating material flow, the air flow is introduced to the V shaped grooves through the slit from a body to collide and mix with the coating material flow ejected from the coating material ejection opening increasing air fluid contact area. As a result thereof, it is possible, even if a low pressure air flow is employed, to effectively atomize the ejected coating material up to a central portion thereof.